Controlling the lateral and vertical dimensions of Bi₂Se₃ nanoplates via seeded growth

Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi₂Se₃ nanoplates with modifiable morphology. By manipulating the rate at which precursor solutions were injected into seeds solution with syringe pumps, two distinctive growth modes could be realized. With a fast injection, the thickness of Bi₂Se₃ nanoplates slightly increased from ~7.5 nm (seeds) to ~9.5 nm while the edge length grew up from ~160 nm (seeds) to ~12 μm, after 6 successive rounds of seeded growth. With a slow injection, the thickness and edge length increased simultaneously to ~35 nm and ~6 μm after 6 rounds of growth, respectively. These two modes could be viewed as a competition between atomic deposition and surface migration. The products showed interesting, thickness-dependent Raman properties. In addition, NIR transparent, highly conductive and flexible Bi₂Se₃ thin films with different thicknesses were constructed by the assembly of the as-synthesized Bi₂Se₃ nanoplates. This approach based on seeded growth and kinetic control can significantly promote the development of versatile nanostructures with diverse morphology.